Plaster board.



No. 694ML (No Model.)

Patented Feb. 25, |902..

` J. SCHRATWIESER.

PLASTER BOARD.

(Application tiled Har. 18, 1901.)

UNITED STATES i PATENT OFruCE.

JACOB SCIIRATWIES'ER, OF BROOKLYN, NEW YORK.

PLASTER BOARD.

`t`PECIFICATION forming part of Letters Patent No. 694,111, dated February 25, 1902.

Application tiled March 13 1901. Serial No. 50,961 (No model.)

ATo @ZZ whom 'it may con/cern:

lmaterial adapted to be used in constructing.

walls, ceilings, and other parts of buildings; and its objects are, among others, to provide a board of strong and durable construction which may be readily applied and will afford an advantageous surface for the application of ealcimine or other tinishing-coat for said walls, &c. It is illustrated in the accompanying drawings referred to, and in which- Figure l is a plan view of parts of boards constructed according to my invcntionwith the layers of which the same are composed partly out away. Fig. 2 is a vertical section of the same on the line 2 2 of Fig. 1. Fig. 3 is -4 a like section of a modification.

A sheet or layer of asbestos, paper, cloth, or other material A, provided with perforations a., constitutes the core or middle layer of the board. This layer, however, may, it desired, be placed upon one side of the other material. The plaster, concrete, or other substance B surrounds the core Aand is preferably provided with perforations b, extending through from side to side and also through perforations a of the core, which are in my preferred construction of greater diameter than the perforations b. One or more edges of the board thus formed are corrugated, as shown at b2, so that when two boards are placed with their edges against each other an irregular break is providedbetween them, into which the plaster or other finishing-coat will enter when applied thereon, thus securing the two boards together and ou account of the irregularity of the break preventing a crack from being formed in the wall from the shrinking of the same or vibration ofthe building or from other causes. One surface of the board is also provided with a rough surface, as shown in Fig. 1, for the purpose of assisting the inishing-coat in adhering thereto.

The perforations b (shown in Fie. only part way through-the board and are not 3) extend disposed at a right angle thereto, so that the plaster when it enters the same will form a key and be prevented from becoming loosened and falling ott. The perforations b are also for the purpose of holding the plaster, and the perforations o., being of lesser diameter than the perforations b,will allow the plaster on either side of the core to pass therethrough, thus uniting the same on both sides 0f said core. The perforations b also provide a convenient place for nailing the board when so desired. In order te still further unite the plaster or other material lB, additional perforations a' are providedin the core, through which the plaster will pass, and in the modification shown in Fig. 3 the perform tions extending through the board E may be entirely. omitted, and the perforations a will then serve the purpose simply of uniting the board B on both sides of the core. The size and shape of the perforations are immaterial,

and they may be either round, square, oblong, or of other form.

1. A plaster board comprising layers of different material, each provided with perforations and the material of one layer passing through the perforations of the other.

2. A plaster board comprising two or more layers of different material, provided with perforatious', the material and perforations of one layer passing through the perforations of the other.

3. In a plaster board, the combination of layers of different material, and perforations in two or more. of the layers, the perforations of one layer being of lesser diameter than those of another.

4. In a plaster board, the combination of layers of different material, and perforations in two or more of the layers, the perforations of one layer being of lesser diameter than those of another and passing therethrough.

5. A plaster board provided with projec tions and indentations on one or more of its edges, the said projections and inde'ntations being of unequal length.

Signed at the city of New York this 15th day of January, 1901.

' JACOB SCHRATWIESER. Witnesses:

ALBERT A. W-ovERMANN', MABEL K. WHITMAN. 

